Doubtful and Unsolvable

Doubtful

Doubtful adjective - Not feeling sure about the truth, wisdom, or trustworthiness of someone or something.

Unsolvable and doubtful are semantically related. In some cases you can use "Unsolvable" instead an adjective "Doubtful".

Unsolvable

Unsolvable adjective - Incapable of being solved or accomplished.
Usage example: an apparently unsolvable problem

Doubtful and unsolvable are semantically related. Sometimes you can use "Doubtful" instead an adjective "Unsolvable".
Cite this Source
Unsolvable and Doubtful. (2016). Retrieved 2026, July 28, from https://thesaurus.plus/related/doubtful/unsolvable
Doubtful & Unsolvable. N.p., 2016. Web. 28 Jul. 2026. <https://thesaurus.plus/related/doubtful/unsolvable>.
Unsolvable or Doubtful. 2016. Accessed July 28, 2026. https://thesaurus.plus/related/doubtful/unsolvable.
Google Ngram Viewer shows how "doubtful" and "unsolvable" have occurred on timeline